//
// detail/reactive_socket_service_base.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_BASE_HPP
#define ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_BASE_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/config.hpp"

#if !defined(ASIO_HAS_IOCP) \
 && !defined(ASIO_WINDOWS_RUNTIME) \
 && !defined(ASIO_HAS_IO_URING_AS_DEFAULT)

#include "asio/associated_cancellation_slot.hpp"
#include "asio/buffer.hpp"
#include "asio/cancellation_type.hpp"
#include "asio/error.hpp"
#include "asio/execution_context.hpp"
#include "asio/socket_base.hpp"
#include "asio/detail/buffer_sequence_adapter.hpp"
#include "asio/detail/memory.hpp"
#include "asio/detail/reactive_null_buffers_op.hpp"
#include "asio/detail/reactive_socket_recv_op.hpp"
#include "asio/detail/reactive_socket_recvmsg_op.hpp"
#include "asio/detail/reactive_socket_send_op.hpp"
#include "asio/detail/reactive_wait_op.hpp"
#include "asio/detail/reactor.hpp"
#include "asio/detail/reactor_op.hpp"
#include "asio/detail/socket_holder.hpp"
#include "asio/detail/socket_ops.hpp"
#include "asio/detail/socket_types.hpp"

#include "asio/detail/push_options.hpp"

namespace asio {
    namespace detail {

        class reactive_socket_service_base {
        public:
            // The native type of a socket.
            typedef socket_type native_handle_type;

            // The implementation type of the socket.
            struct base_implementation_type {
                // The native socket representation.
                socket_type socket_;

                // The current state of the socket.
                socket_ops::state_type state_;

                // Per-descriptor data used by the reactor.
                reactor::per_descriptor_data reactor_data_;
            };

            // Constructor.
            ASIO_DECL reactive_socket_service_base(execution_context &context);

            // Destroy all user-defined handler objects owned by the service.
            ASIO_DECL void base_shutdown();

            // Construct a new socket implementation.
            ASIO_DECL void construct(base_implementation_type &impl);

            // Move-construct a new socket implementation.
            ASIO_DECL void base_move_construct(base_implementation_type &impl,
                                               base_implementation_type &other_impl)

            ASIO_NOEXCEPT;

            // Move-assign from another socket implementation.
            ASIO_DECL void base_move_assign(base_implementation_type &impl,
                                            reactive_socket_service_base &other_service,
                                            base_implementation_type &other_impl);

            // Destroy a socket implementation.
            ASIO_DECL void destroy(base_implementation_type &impl);

            // Determine whether the socket is open.
            bool is_open(const base_implementation_type &impl) const {
                return impl.socket_ != invalid_socket;
            }

            // Destroy a socket implementation.
            ASIO_DECL asio::error_code
            close(
                    base_implementation_type
            & impl,
            asio::error_code &ec
            );

            // Release ownership of the socket.
            ASIO_DECL socket_type
            release(
                    base_implementation_type
            & impl,
            asio::error_code &ec
            );

            // Get the native socket representation.
            native_handle_type native_handle(base_implementation_type &impl) {
                return impl.socket_;
            }

            // Cancel all operations associated with the socket.
            ASIO_DECL asio::error_code
            cancel(
                    base_implementation_type
            & impl,
            asio::error_code &ec
            );

            // Determine whether the socket is at the out-of-band data mark.
            bool at_mark(const base_implementation_type &impl,
                         asio::error_code &ec) const {
                return socket_ops::sockatmark(impl.socket_, ec);
            }

            // Determine the number of bytes available for reading.
            std::size_t available(const base_implementation_type &impl,
                                  asio::error_code &ec) const {
                return socket_ops::available(impl.socket_, ec);
            }

            // Place the socket into the state where it will listen for new connections.
            asio::error_code listen(base_implementation_type &impl,
                                    int backlog, asio::error_code &ec) {
                socket_ops::listen(impl.socket_, backlog, ec);
                return ec;
            }

            // Perform an IO control command on the socket.
            template<typename IO_Control_Command>
            asio::error_code io_control(base_implementation_type &impl,
                                        IO_Control_Command &command, asio::error_code &ec) {
                socket_ops::ioctl(impl.socket_, impl.state_, command.name(),
                                  static_cast<ioctl_arg_type *>(command.data()), ec);
                return ec;
            }

            // Gets the non-blocking mode of the socket.
            bool non_blocking(const base_implementation_type &impl) const {
                return (impl.state_ & socket_ops::user_set_non_blocking) != 0;
            }

            // Sets the non-blocking mode of the socket.
            asio::error_code non_blocking(base_implementation_type &impl,
                                          bool mode, asio::error_code &ec) {
                socket_ops::set_user_non_blocking(impl.socket_, impl.state_, mode, ec);
                return ec;
            }

            // Gets the non-blocking mode of the native socket implementation.
            bool native_non_blocking(const base_implementation_type &impl) const {
                return (impl.state_ & socket_ops::internal_non_blocking) != 0;
            }

            // Sets the non-blocking mode of the native socket implementation.
            asio::error_code native_non_blocking(base_implementation_type &impl,
                                                 bool mode, asio::error_code &ec) {
                socket_ops::set_internal_non_blocking(impl.socket_, impl.state_, mode, ec);
                return ec;
            }

            // Wait for the socket to become ready to read, ready to write, or to have
            // pending error conditions.
            asio::error_code wait(base_implementation_type &impl,
                                  socket_base::wait_type w, asio::error_code &ec) {
                switch (w) {
                    case socket_base::wait_read:
                        socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);
                        break;
                    case socket_base::wait_write:
                        socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);
                        break;
                    case socket_base::wait_error:
                        socket_ops::poll_error(impl.socket_, impl.state_, -1, ec);
                        break;
                    default:
                        ec = asio::error::invalid_argument;
                        break;
                }

                return ec;
            }

            // Asynchronously wait for the socket to become ready to read, ready to
            // write, or to have pending error conditions.
            template<typename Handler, typename IoExecutor>
            void async_wait(base_implementation_type &impl,
                            socket_base::wait_type w, Handler &handler, const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_wait_op <Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, handler, io_ex);

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_wait"));

                int op_type;
                switch (w) {
                    case socket_base::wait_read:
                        op_type = reactor::read_op;
                        break;
                    case socket_base::wait_write:
                        op_type = reactor::write_op;
                        break;
                    case socket_base::wait_error:
                        op_type = reactor::except_op;
                        break;
                    default:
                        p.p->ec_ = asio::error::invalid_argument;
                        reactor_.post_immediate_completion(p.p, is_continuation);
                        p.v = p.p = 0;
                        return;
                }

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, op_type);
                }

                start_op(impl, op_type, p.p, is_continuation, false, false);
                p.v = p.p = 0;
            }

            // Send the given data to the peer.
            template<typename ConstBufferSequence>
            size_t send(base_implementation_type &impl,
                        const ConstBufferSequence &buffers,
                        socket_base::message_flags flags, asio::error_code &ec) {
                typedef buffer_sequence_adapter <asio::const_buffer,
                ConstBufferSequence> bufs_type;

                if (bufs_type::is_single_buffer) {
                    return socket_ops::sync_send1(impl.socket_,
                                                  impl.state_, bufs_type::first(buffers).data(),
                                                  bufs_type::first(buffers).size(), flags, ec);
                } else {
                    bufs_type bufs(buffers);
                    return socket_ops::sync_send(impl.socket_, impl.state_,
                                                 bufs.buffers(), bufs.count(), flags, bufs.all_empty(), ec);
                }
            }

            // Wait until data can be sent without blocking.
            size_t send(base_implementation_type &impl, const null_buffers &,
                        socket_base::message_flags, asio::error_code &ec) {
                // Wait for socket to become ready.
                socket_ops::poll_write(impl.socket_, impl.state_, -1, ec);

                return 0;
            }

            // Start an asynchronous send. The data being sent must be valid for the
            // lifetime of the asynchronous operation.
            template<typename ConstBufferSequence, typename Handler, typename IoExecutor>
            void async_send(base_implementation_type &impl,
                            const ConstBufferSequence &buffers, socket_base::message_flags flags,
                            Handler &handler, const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_socket_send_op <
                ConstBufferSequence, Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, impl.socket_,
                                  impl.state_, buffers, flags, handler, io_ex);

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, reactor::write_op);
                }

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_send"));

                start_op(impl, reactor::write_op, p.p, is_continuation, true,
                         ((impl.state_ & socket_ops::stream_oriented)
                          && buffer_sequence_adapter<asio::const_buffer,
                                 ConstBufferSequence>::all_empty(buffers)));
                p.v = p.p = 0;
            }

            // Start an asynchronous wait until data can be sent without blocking.
            template<typename Handler, typename IoExecutor>
            void async_send(base_implementation_type &impl, const null_buffers &,
                            socket_base::message_flags, Handler &handler, const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_null_buffers_op <Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, handler, io_ex);

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, reactor::write_op);
                }

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_send(null_buffers)"));

                start_op(impl, reactor::write_op, p.p, is_continuation, false, false);
                p.v = p.p = 0;
            }

            // Receive some data from the peer. Returns the number of bytes received.
            template<typename MutableBufferSequence>
            size_t receive(base_implementation_type &impl,
                           const MutableBufferSequence &buffers,
                           socket_base::message_flags flags, asio::error_code &ec) {
                typedef buffer_sequence_adapter <asio::mutable_buffer,
                MutableBufferSequence> bufs_type;

                if (bufs_type::is_single_buffer) {
                    return socket_ops::sync_recv1(impl.socket_,
                                                  impl.state_, bufs_type::first(buffers).data(),
                                                  bufs_type::first(buffers).size(), flags, ec);
                } else {
                    bufs_type bufs(buffers);
                    return socket_ops::sync_recv(impl.socket_, impl.state_,
                                                 bufs.buffers(), bufs.count(), flags, bufs.all_empty(), ec);
                }
            }

            // Wait until data can be received without blocking.
            size_t receive(base_implementation_type &impl, const null_buffers &,
                           socket_base::message_flags, asio::error_code &ec) {
                // Wait for socket to become ready.
                socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);

                return 0;
            }

            // Start an asynchronous receive. The buffer for the data being received
            // must be valid for the lifetime of the asynchronous operation.
            template<typename MutableBufferSequence,
                    typename Handler, typename IoExecutor>
            void async_receive(base_implementation_type &impl,
                               const MutableBufferSequence &buffers, socket_base::message_flags flags,
                               Handler &handler, const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_socket_recv_op <
                MutableBufferSequence, Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, impl.socket_,
                                  impl.state_, buffers, flags, handler, io_ex);

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, reactor::read_op);
                }

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_receive"));

                start_op(impl,
                         (flags & socket_base::message_out_of_band)
                         ? reactor::except_op : reactor::read_op,
                         p.p, is_continuation,
                         (flags & socket_base::message_out_of_band) == 0,
                         ((impl.state_ & socket_ops::stream_oriented)
                          && buffer_sequence_adapter<asio::mutable_buffer,
                                 MutableBufferSequence>::all_empty(buffers)));
                p.v = p.p = 0;
            }

            // Wait until data can be received without blocking.
            template<typename Handler, typename IoExecutor>
            void async_receive(base_implementation_type &impl,
                               const null_buffers &, socket_base::message_flags flags,
                               Handler &handler, const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_null_buffers_op <Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, handler, io_ex);

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, reactor::read_op);
                }

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_receive(null_buffers)"));

                start_op(impl,
                         (flags & socket_base::message_out_of_band)
                         ? reactor::except_op : reactor::read_op,
                         p.p, is_continuation, false, false);
                p.v = p.p = 0;
            }

            // Receive some data with associated flags. Returns the number of bytes
            // received.
            template<typename MutableBufferSequence>
            size_t receive_with_flags(base_implementation_type &impl,
                                      const MutableBufferSequence &buffers,
                                      socket_base::message_flags in_flags,
                                      socket_base::message_flags &out_flags, asio::error_code &ec) {
                buffer_sequence_adapter <asio::mutable_buffer,
                MutableBufferSequence> bufs(buffers);

                return socket_ops::sync_recvmsg(impl.socket_, impl.state_,
                                                bufs.buffers(), bufs.count(), in_flags, out_flags, ec);
            }

            // Wait until data can be received without blocking.
            size_t receive_with_flags(base_implementation_type &impl,
                                      const null_buffers &, socket_base::message_flags,
                                      socket_base::message_flags &out_flags, asio::error_code &ec) {
                // Wait for socket to become ready.
                socket_ops::poll_read(impl.socket_, impl.state_, -1, ec);

                // Clear out_flags, since we cannot give it any other sensible value when
                // performing a null_buffers operation.
                out_flags = 0;

                return 0;
            }

            // Start an asynchronous receive. The buffer for the data being received
            // must be valid for the lifetime of the asynchronous operation.
            template<typename MutableBufferSequence,
                    typename Handler, typename IoExecutor>
            void async_receive_with_flags(base_implementation_type &impl,
                                          const MutableBufferSequence &buffers, socket_base::message_flags in_flags,
                                          socket_base::message_flags &out_flags, Handler &handler,
                                          const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_socket_recvmsg_op <
                MutableBufferSequence, Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, impl.socket_,
                                  buffers, in_flags, out_flags, handler, io_ex);

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, reactor::read_op);
                }

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_receive_with_flags"));

                start_op(impl,
                         (in_flags & socket_base::message_out_of_band)
                         ? reactor::except_op : reactor::read_op,
                         p.p, is_continuation,
                         (in_flags & socket_base::message_out_of_band) == 0, false);
                p.v = p.p = 0;
            }

            // Wait until data can be received without blocking.
            template<typename Handler, typename IoExecutor>
            void async_receive_with_flags(base_implementation_type &impl,
                                          const null_buffers &, socket_base::message_flags in_flags,
                                          socket_base::message_flags &out_flags, Handler &handler,
                                          const IoExecutor &io_ex) {
                bool is_continuation =
                        asio_handler_cont_helpers::is_continuation(handler);

                typename associated_cancellation_slot<Handler>::type slot
                        = asio::get_associated_cancellation_slot(handler);

                // Allocate and construct an operation to wrap the handler.
                typedef reactive_null_buffers_op <Handler, IoExecutor> op;
                typename op::ptr p = {asio::detail::addressof(handler),
                                      op::ptr::allocate(handler), 0};
                p.p = new(p.v) op(success_ec_, handler, io_ex);

                // Optionally register for per-operation cancellation.
                if (slot.is_connected()) {
                    p.p->cancellation_key_ =
                            &slot.template emplace<reactor_op_cancellation>(
                                    &reactor_, &impl.reactor_data_, impl.socket_, reactor::read_op);
                }

                ASIO_HANDLER_CREATION((reactor_.context(), *p.p, "socket",
                        &impl, impl.socket_, "async_receive_with_flags(null_buffers)"));

                // Clear out_flags, since we cannot give it any other sensible value when
                // performing a null_buffers operation.
                out_flags = 0;

                start_op(impl,
                         (in_flags & socket_base::message_out_of_band)
                         ? reactor::except_op : reactor::read_op,
                         p.p, is_continuation, false, false);
                p.v = p.p = 0;
            }

        protected:
            // Open a new socket implementation.
            ASIO_DECL asio::error_code
            do_open(
                    base_implementation_type
            & impl,
            int af,
            int type,
            int protocol, asio::error_code
            & ec);

            // Assign a native socket to a socket implementation.
            ASIO_DECL asio::error_code
            do_assign(
                    base_implementation_type
            & impl,
            int type,
            const native_handle_type &native_socket, asio::error_code
            & ec);

            // Start the asynchronous read or write operation.
            ASIO_DECL void start_op(base_implementation_type &impl, int op_type,
                                    reactor_op *op, bool is_continuation, bool is_non_blocking, bool noop);

            // Start the asynchronous accept operation.
            ASIO_DECL void start_accept_op(base_implementation_type &impl,
                                           reactor_op *op, bool is_continuation, bool peer_is_open);

            // Start the asynchronous connect operation.
            ASIO_DECL void start_connect_op(base_implementation_type &impl,
                                            reactor_op *op, bool is_continuation,
                                            const socket_addr_type *addr, size_t addrlen);

            // Helper class used to implement per-operation cancellation
            class reactor_op_cancellation {
            public:
                reactor_op_cancellation(reactor *r,
                                        reactor::per_descriptor_data *p, int d, int o)
                        : reactor_(r),
                          reactor_data_(p),
                          descriptor_(d),
                          op_type_(o) {
                }

                void operator()(cancellation_type_t type) {
                    if (!!(type &
                           (cancellation_type::terminal
                            | cancellation_type::partial
                            | cancellation_type::total))) {
                        reactor_->cancel_ops_by_key(descriptor_,
                                                    *reactor_data_, op_type_, this);
                    }
                }

            private:
                reactor *reactor_;
                reactor::per_descriptor_data *reactor_data_;
                int descriptor_;
                int op_type_;
            };

            // The selector that performs event demultiplexing for the service.
            reactor &reactor_;

            // Cached success value to avoid accessing category singleton.
            const asio::error_code success_ec_;
        };

    } // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#if defined(ASIO_HEADER_ONLY)
# include "asio/detail/impl/reactive_socket_service_base.ipp"
#endif // defined(ASIO_HEADER_ONLY)

#endif // !defined(ASIO_HAS_IOCP)
//   && !defined(ASIO_WINDOWS_RUNTIME)
//   && !defined(ASIO_HAS_IO_URING_AS_DEFAULT)

#endif // ASIO_DETAIL_REACTIVE_SOCKET_SERVICE_BASE_HPP
